WO2017009281A1

WO2017009281A1 - Optoelectronic semiconductor component and method for producing an optoelectronic semiconductor component

Info

Publication number: WO2017009281A1
Application number: PCT/EP2016/066418
Authority: WO
Inventors: Johannes Baur; Jürgen Moosburger; Lutz Höppel; Markus Maute; Thomas Schwarz; Matthias Sabathil; Ralph Wirth; Alexander Linkov
Original assignee: Osram Opto Semiconductors Gmbh
Priority date: 2015-07-16
Filing date: 2016-07-11
Publication date: 2017-01-19
Also published as: TWI626763B; DE102015111573A1; US10276752B2; US20190006562A1; TW201709552A

Abstract

The invention relates to an optoelectronic semiconductor component (10), comprising a light-emitting semiconductor body (1) having a radiating side (1a), a current spreading layer (2) arranged on the radiating side (1a) of the semiconductor body (1) and covering the same, at least in part. The current spreading layer (2) comprises an electrically conductive material (2a) that is transparent to the light radiated by the semiconductor body (1), and particles (2b) of an additional material, and an electrical contact (3) that is arranged on the side (2c) of the current spreading layer (2) that is facing away from the semiconductor body (1).

Description

description

Optoelectronic semiconductor device and method for

Production of an optoelectronic semiconductor component

The invention relates to an optoelectronic

Semiconductor device and a method for producing an optoelectronic semiconductor device. In surface-emitting semiconductor devices having a top-side contact, the light emission across the top thereof can be reduced by contact structures. For flat current injection in semiconductor layers of a surface-emitting semiconductor component, a layer for current spreading can be arranged on the semiconductor component, which is transparent. The expansion of

reflective or at least shadowing

Contact structures can thereby be reduced on the emission side of the semiconductor device. To the efficient

Outcoupling of the light from the semiconductor device has conventional transparent current spreading layers

However, too low a refractive index, whereby an excessive proportion of the light by total reflection at the

Interface between the semiconductor body and the

Stromaufweitungsschicht remains in the semiconductor device.

The invention is based on the object

Semiconductor component with an improved contacting of a semiconductor body at its radiating top in

With regard to an improved current impression in the

Semiconductor body and improved coupling of

Specify radiation and a method for producing such a contact. This object is achieved by a product and a method according to the independent patent claims. Advantageous embodiments and further developments of the invention are

Subject of the dependent claims.

An optoelectronic semiconductor component comprises a light-emitting semiconductor body having a radiation side, a current spreading layer which is arranged on the emission side of the semiconductor body and at least thereof

partially covers, wherein the current spreading layer comprises a light emitted from the semiconductor body light transparent electrically conductive material and particles of another material, and an electrical contact, which on a side facing away from the semiconductor body of the

Current spreading layer is arranged.

The light-emitting semiconductor body may advantageously be formed as a surface-emitting semiconductor chip. The semiconductor body is advantageously contacted from the emission side, whereby by means of the current expansion layer as homogeneous as possible a current distribution over the

Abstrahlseite and current injection is achieved in the semiconductor body. In order to ensure radiation as well as contact of the semiconductor body with the current spreading layer, it comprises a transparent and electrically conductive material, for example ITO or zinc oxide. The current spreading layer advantageously covers the semiconductor body at the emission side at least partially. Furthermore, it is possible for the current spreading layer to have a

Area of an active zone of the semiconductor body, in which During operation of the semiconductor device, light is generated, partially or completely covered. It is also advantageously possible that the current spreading layer completely covers the emission side.

Through an electrical contact on the

Current spreading layer is a current in the

Stromaufungsungsschicht fed, wherein the electric

Contact the current spreading layer not beneficial

completely covered. Advantageously, a surface coverage of the electrical contact on the current spreading layer is much smaller than a surface occupation of the current spreading layer on the semiconductor body. Thereby, a shading effect by the electrical contact for light which is ausgekopplet by the Stromaufweitungsschicht is reduced.

The particles of the further material are advantageously distributed as homogeneously as possible in the current spreading layer. By means of the particles, optical properties and the electrical conductivity of the current spreading layer can advantageously be influenced. The transparent electrically conductive material and the particles of the further material advantageously form a composite material, which the

Stromaufweitungsschicht forms.

According to one embodiment of the optoelectronic

Semiconductor device, the particles of the further material have a refractive index n3, which is different from a refractive index nl of the transparent material.

The optical properties of the current spreading layer are determined by the refractive index of the materials containing the

Current spreading layer includes influenced. Advantageous For example, the particles may be homogeneously distributed in the transparent material of the current spreading layer, whereby a homogeneous change of a mean refractive index n 2 of the

Stromaufweitungsschicht results. The middle one

Refractive index n2 of the current spreading layer is between the refractive indices of the transparent material n1 and the particle n3. This changes the middle one

Refractive index n2 depending on the proportion of materials with refractive indices nl and n3.

According to one embodiment of the optoelectronic

Semiconductor component, the refractive index n3 of the particles of the other material is greater than the refractive index nl of the transparent material.

With a refractive index n3 of the particles which is greater than the refractive index n1 of the transparent material, the average refractive index n2 is increased to a corresponding extent depending on the proportion of the particles in the current spreading layer of n1. In this way, the particles change the transmission properties of the current spreading layer for light. With an altered average refractive index n2, the angular condition for total reflection of light at the interface of the current spreading layer and the semiconductor body changes, and hence, the

Outcoupling efficiency from the semiconductor body on which the Stromaufweitungsschicht is arranged increases.

According to one embodiment of the optoelectronic

Semiconductor devices include the particles further

Materials Ti0 ₂ . The particles which Ti02 ^~ comprise particles allow an increase in the average refractive index n2 and are advantageously used together with the transparent material to form the current spreading layer as a composite material. Advantageously, by deliberately introducing the particles into the current spreading layer, an electrical resistance of the current spreading layer can be minimized and the outcoupling of light simultaneously maximized. According to one embodiment of the optoelectronic

Semiconductor device, the transparent material comprises a transparent conductive oxide.

As a transparent conductive oxide is particularly suitable ITO. Advantageously it is possible that ITO together with

Particles of a further material is applied to a radiation side of the semiconductor body and the

Stromweitweitungsschicht forms as a composite material. Due to the electrical conductivity of the ITO, the

Stromaufweitungsschicht be connected via an electrical contact.

According to one embodiment of the optoelectronic

Semiconductor component, the current spreading layer has a mean refractive index n2 of greater than or equal to 2.

To increase the extraction of light from the

Semiconductor body, it proves to be advantageous that the average refractive index n2 of the current spreading layer is greater than two in order to reduce a total reflection of light in the transition between the semiconductor body and current spreading layer. Since transparent conductive oxides, in particular ITO, have a refractive index of less than two can the mean refractive index n2 of the current spreading layer may advantageously be increased by the particles of the further material above the value of two. According to one embodiment of the optoelectronic

Semiconductor component, the electrical contact is at least partially formed as a contact web.

The electrical contact comprises, for example

Connection point at which a contacting by means of a bonding wire or other components takes place. Farther

Advantageously, the contact extends as a contact web over a radiation side of the current spreading layer and has one in relation to the width of the

Current spreading layer narrow width, for example, at most 10% of the width of the Stromaufweitungsschicht on. Thus, a contacting of the current spreading layer can be achieved and shading effects can be minimized by the contact. Advantageously, the contact web has a width of less than 20%, advantageously less than 10% or less than 5% of the width of the

Stromaufweitungsschicht on.

According to one embodiment of the optoelectronic

Semiconductor component is disposed between the current spreading layer and the semiconductor body, a further layer which comprises a transparent conductive material and is free of the particles of the further material. The further layer advantageously comprises a transparent conductive oxide. However, the further layer advantageously does not comprise particles of the further material.

Advantageously, the further layer has a refractive index n4 which, for example, is equal to the refractive index n1 of the transparent conductive material of the

Current spreading layer and is less than the mean refractive index n2 of the current spreading layer. By means of such a further layer, it is advantageously possible to minimize the electrical resistance below the current spreading layer and the current from the current spreading layer

can be advantageously embossed well into the semiconductor body. Although by the further layer by the

Current spreading layer attenuated improved outcoupling of the light from the semiconductor body, however, the output compared to a conventional

Nevertheless, the current spreading layer may be increased if the thickness of the further layer does not exceed a critical value. The further layer advantageously has a thickness of less than or equal to 30 nm. In this way, a simultaneous reduction of electrical resistance and a

Optimization of the extraction of light by the others

Layer achieved.

According to one embodiment of the optoelectronic

Semiconductor device includes the semiconductor device

Sapphire substrate. The light-emitting semiconductor body may advantageously comprise a semiconductor layer sequence which is disposed on a

Sapphire substrate is applied.

In a method for manufacturing an optoelectronic semiconductor device, a light emitting

Semiconductor body provided. Furthermore, a

Making a current spreading layer, through

simultaneous application of one for the semiconductor body radiated light transparent electrically conductive

Material and particles of a further material on a radiation side of the semiconductor body, wherein the

Stromaufweitungsschicht the emission side of the

Semiconductor body at least partially covered. Furthermore, an electrical contact is arranged on the current spreading layer.

On the advantageous as surface emitting

Semiconductor chip formed light-emitting

Semiconductor bodies can by deposition processes

different materials on the emission side

be applied so that these after application

advantageously a solid composite material as

Form current spreading layer. The shares of

can be applied during the

Applying process can be adapted to a specification and the materials are advantageously distributed homogeneously over the emission side of the semiconductor body. So it is also possible, a sequence of layers on the

Apply semiconductor body in which vary the proportions of the materials. Thus, for example, a further layer which advantageously comprises a transparent electrically conductive material but no particles of a further material can be arranged between the semiconductor body and the current spreading layer comprising the particles of the further material.

To increase a mean refractive index of

Stromaufweitungsschicht can be increased, the proportion of particles of another material. In accordance with at least one embodiment of the method, the production of the current spreading layer takes place by means of

simultaneous sputtering of the transparent material and the particles of the further material.

Sputtering is well suited to materials such as transparent conductive oxides as well as particles

For example, T1O ₂ on a radiating surface of the

Apply semiconductor body, in particular applied simultaneously, while controlling the proportion of the respective materials on the radiating surface. Furthermore, sputtering is also suitable for distributing the materials as far as possible homogeneously over the emission surface when applied to the emission surface and for advantageously forming various materials as a composite material. Alternatively, the transparent conductive material and the particles of the further material may be evaporated.

In accordance with at least one embodiment of the method, in the production of the current spreading layer, a proportion of the transparent material and a proportion of the particles of the further material for setting a middle one

Refractive index n2 of the current spreading layer to a

adjusted given size.

Advantageously, the particles of the further material have a higher refractive index n3 than the transparent conductive material. For example, to achieve an improved output from the semiconductor body, the middle

Refractive index n2 of the current spreading layer through the

Increases the proportion of particles of the further material when applying the transparent material and the particles.

According to the desired degree of decoupling can at Applying the proportion of particles or the proportion of the transparent material in the composite of the

Current spreading layer can be adjusted so that a

given average refractive index n2 of

Current spreading layer is achieved. It is also possible that during the application of the shares of

Particles and the transparent material are changed and thus the proportions and the average refractive index n2 of the current spreading layer within the finished

Stromaufweitungsschicht vary with distance from the radiating surface of the semiconductor body.

Further advantages, advantageous embodiments and

Further developments emerge from the following in

Connection with the embodiment described embodiment.

Show it:

FIGS. 1 a and 1 b show an optoelectronic semiconductor component in a schematic side view,

FIGS. 2 a, 2 b and 2 c show an electrical contact on a current spreading layer, and FIG. 3 shows a current spreading layer on a semiconductor body.

Identical or equivalent elements are each provided with the same reference numerals in the figures. The components shown in the figures and the

Size ratios of the components with each other are not to be considered as true to scale. FIG. 1 a shows a schematic side view of an optoelectronic semiconductor component 10 with a light-emitting semiconductor body 1 with a radiation side 1 a, on which a current spreading layer 2 is arranged and partially covers the emission side 1 a. By the

Stromaufweitungsschicht 2 is advantageous power from an electrical contact 3, which on a the

Semiconductor body 1 facing away from the

Current spreading layer 2 is arranged in the

Semiconductor body 1 is fed, wherein the current is advantageously fed over the entire contact surface of the current spreading layer 2 with the emission side la of the semiconductor body 1 in this. To a shadowing of the radiated

To minimize light, the electrical contact 3 only on the smallest possible portion on the

Current spreading layer 2 is arranged.

Furthermore, Figure la shows that the

Stromaufweitungsschicht 2 a transparent to the light emitted from the semiconductor body 1 light electrically conductive

Material _{2 a and 2} b of a further material comprises, wherein the transparent electrically conductive material _{2 a} comprises, for example, ITO and the particles ₂ b comprise, for example, T1O ₂ . The particles 2b and the transparent

electrically conductive material 2a form the

Stromaufweitungsschicht 2 here as a solid

Composite material and the particles 2b are advantageously distributed homogeneously in the current spreading layer 2. The particles 2b have a refractive index n3, which is advantageously greater than a refractive index n1 of the

transparent material. In this case, a refractive index resulting in the material composite of the current spreading layer 2 n2 depending on the proportion of particles 2b in the

Current spreading layer 2 of the value nl of the refractive index of the transparent material 2a increases. This causes a change in the transmission properties of

Current spreading layer 2 for light over a

Stromaufweitungsschicht 2 without particles 2b, which the

Angular condition for total reflection of light at the interface of the current spreading layer and the

Semiconductor body changed. With a reduced

Total reflection of light at the interface of the

Semiconductor body with the current spreading layer 2, the Auskopplungseffizienz from the semiconductor body is increased.

FIG. 1b shows an optoelectronic semiconductor component 10 similar to FIG. 1a with the difference that the

Stromaufweitungsschicht 2 on the emission side la of

Semiconductor body 1 comprises a further layer 9, which comprises a transparent conductive material 2a and is free of the particles of the further material.

The further layer 9 has a refractive index n4 which, for example, is equal to the refractive index n1 of the transparent conductive material of the

Current spreading layer 2 and is less than the average refractive index n2 of the current spreading layer with the particles of the further material. The further layer 9 advantageously has a thickness D of less than or equal to 30 nm. However, the thickness D of the further layer 9

advantageously be at least 10 nm. As a result, the further layer 9 is thin enough that it advantageously does not act purely optically on the photons from the semiconductor body and a wave function of the photons at the interface of the semiconductor body with the further layer with the Stromaufweitungsschicht 2 can interact with the particles 2b. In this way, a simultaneous reduction of electrical resistance to current injection in the

Semiconductor body 1 and an optimization of the coupling of light through the further layer 9 achieved. The others

Layer 9 may be formed as a separate layer.

FIG. 2 a shows a top view of an optoelectronic semiconductor component 10, wherein an electrical contact 3 is arranged on a current spreading layer 2. A

Junction S is disposed on the Stromaufweitungsschicht 2, at which a contacting by means

for example, a bonding wire takes place. The

Current spreading layer 2 comprises a contact web K, which advantageously has a width of less than 20%, advantageously less than 10% or less than 5% of the width of the current spreading layer 2.

The compared to the current spreading layer 2

relatively narrow design of the contact land minimizes the shadowing effects of the contact. 3

FIG. 2b shows the electrical contact 3 on the

Current spreading layer 2 of Figure 2a in one

schematic side sectional view taken along a line A of Figure 2a. The semiconductor body 1 may comprise, for example, a sapphire substrate.

FIG. 2c shows an optoelectronic semiconductor component 10 in a plan view, wherein the semiconductor body has no connection point for an external contact on the

Stream spreading layer 2 comprises, but of a

Frame area 3a of which the semiconductor body and the Current spreading layer 2 laterally surrounds a plurality of contact webs K on the emission side of the

Stromaufweitungsschicht 2 are performed. This embodiment is particularly suitable for substrateless semiconductor chips.

FIG. 3 shows the semiconductor body 1 in one

schematic side view during the production of

Stromaufweitungsschicht 2, wherein a for the of

Semiconductor body emitted light transparent electrically conductive material 2a and 2b particles of another

Material on a radiation side la of the semiconductor body 1 are applied, for example by sputtering, and form the current spreading layer 2 as a composite material. Depending on the specification, the proportions of the transparent electrically conductive material 2a and of the particles 2b of a further material can be varied accordingly.

The invention is not limited by the description based on the embodiments of these. Rather, the invention includes every new feature as well as any combination of

Features, which includes in particular any combination of features in the claims, even if this feature or this combination itself is not explicitly in the

Claims or embodiments is given.

This patent application claims the priority of German Patent Application 10 2015 111 573.5, the disclosure of which is hereby incorporated by reference. Reference sign list

1 light-emitting semiconductor body

la radiation side

2 current spreading layer

2a transparent electrically conductive material

2b particles

2c facing away from the semiconductor body side of the

Current spreading layer

3 electrical contact

3a frame area

9 further layer of transparent conductive material D thickness of the further layer

10 optoelectronic semiconductor device

K contact bridge

S connection point

Claims

claims

An optoelectronic semiconductor device (10) comprising

a light-emitting semiconductor body (1) having a radiation side (1a),

a current spreading layer (2) which is connected to the

Abstrahlseite (la) of the semiconductor body (1) is arranged and this at least partially covers, wherein the Stromaufweitungsschicht (2) for the from the

Semiconductor body (1) radiated light transparent electrically conductive material (2a) and particles (2b) comprises a further material, and

- An electrical contact (3) which on a side facing away from the semiconductor body (1) side (2c) of the

Current spreading layer (2) is arranged.

2. Optoelectronic semiconductor device (10) according to the

previous claim,

wherein the particles (2b) of the further material have a refractive index n3, which of a

Refractive index nl of the transparent material (2a) is different.

3. Optoelectronic semiconductor device (10) after the

previous claim,

in which the refractive index n3 of the particles (2b) of the further material is greater than the refractive index n1 of the transparent material (2a).

4. Optoelectronic semiconductor component (10) according to one of the preceding claims,

in which the particles (2b) of the further material T1O ₂ include.

5. Optoelectronic semiconductor component (10) according to one of the preceding claims,

wherein the transparent material (2a) comprises a transparent conductive oxide.

6. Optoelectronic semiconductor component (10) according to one of the preceding claims,

wherein the current spreading layer (2) has a mean refractive index n2 of greater than or equal to 2.

7. Optoelectronic semiconductor component (10) according to one of the preceding claims,

in which the electrical contact (3) is at least partially formed as a contact web.

8. Optoelectronic semiconductor component (10) according to one of the preceding claims,

in which a further layer (9), which comprises a transparent conductive material and is free of the particles (2b) of the further material, is arranged between the current spreading layer (2) and the semiconductor body (1).

9. Optoelectronic semiconductor component (10) according to one of the preceding claims,

wherein the semiconductor device (10) comprises a sapphire substrate.

10. A method for producing an optoelectronic

Semiconductor device (10) with the steps:

- Provide a light-emitting Semiconductor body (1),

- Making a StromaufWeitungsschicht (2), by simultaneously applying a for the of

Semiconductor body (1) radiated light transparent electrically conductive material (2a) and particles (2b) of a further material on a radiation side (la) of the semiconductor body (1), wherein the

Stromaufweitungsschicht (2) the emission side (la) of the semiconductor body (1) at least partially covered, and

- Arranging an electrical contact (3) on the Stromaufweitungsschicht (2).

11. The method according to claim 10,

in which the production of the current spreading layer (2) by means of simultaneous sputtering of the transparent

Materials (2a) and the particles (2b) of the other

Material takes place.

12. The method according to any one of claims 10 or 11,

in which when forming the current spreading layer (2) a portion of the transparent material (2a) and a portion of the particles (2b) of the further material for setting a mean refractive index n2 of

Current spreading layer (2) are adapted to a predetermined size.